diff --git a/.github/workflows/CI.yaml b/.github/workflows/CI.yaml
index 71867ae..2f70d63 100644
--- a/.github/workflows/CI.yaml
+++ b/.github/workflows/CI.yaml
@@ -24,7 +24,7 @@ jobs:
           - aarch64-apple-darwin
           - x86_64-pc-windows-msvc
         toolchain:
-          - 1.74.0 # MSRV
+          - 1.81.0 # MSRV
           - stable
           - nightly
         include:
diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index a0fb20b..7350d20 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -14,6 +14,13 @@ All notable changes to this project will be documented in this file.
 The format is based on https://keepachangelog.com/[Keep a Changelog], and this
 project adheres to https://semver.org/[Semantic Versioning].
 
+== {compare-url}/v0.8.1\...HEAD[Unreleased]
+
+=== Changed
+
+* Make `Error` trait available in `no_std` mode ({pull-request-url}/114[#114])
+* Bump MSRV to 1.81.0 ({pull-request-url}/114[#114])
+
 == {compare-url}/v0.8.0\...v0.8.1[0.8.1] - 2024-07-03
 
 === Changed
diff --git a/Cargo.toml b/Cargo.toml
index 52dd731..696706b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,7 +8,7 @@ name = "sysexits"
 version = "0.8.1"
 authors = ["Shun Sakai <sorairolake@protonmail.ch>"]
 edition = "2021"
-rust-version = "1.74.0"
+rust-version = "1.81.0"
 description = "The system exit codes as defined by <sysexits.h>"
 documentation = "https://docs.rs/sysexits"
 readme = "README.md"
diff --git a/README.md b/README.md
index d19801e..f25b7bd 100644
--- a/README.md
+++ b/README.md
@@ -75,7 +75,7 @@ See the [documentation][docs-url] for more details.
 
 ## Minimum supported Rust version
 
-The minimum supported Rust version (MSRV) of this library is v1.74.0.
+The minimum supported Rust version (MSRV) of this library is v1.81.0.
 
 ## Source code
 
diff --git a/clippy.toml b/clippy.toml
index efb0e67..c037fdb 100644
--- a/clippy.toml
+++ b/clippy.toml
@@ -2,4 +2,4 @@
 #
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
-msrv = "1.74.0"
+msrv = "1.81.0"
diff --git a/src/error.rs b/src/error.rs
index f3f6cc1..e7eff0c 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -5,7 +5,7 @@
 
 //! Error types for this crate.
 
-use core::fmt;
+use core::{error::Error, fmt};
 
 /// The error type indicating that [`ExitCode`](crate::ExitCode) was out of
 /// range.
@@ -19,8 +19,7 @@ impl fmt::Display for ExitCodeRangeError {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for ExitCodeRangeError {}
+impl Error for ExitCodeRangeError {}
 
 #[cfg(feature = "std")]
 /// An error which can be returned when converting an
@@ -59,7 +58,7 @@ impl fmt::Display for TryFromExitStatusError {
 }
 
 #[cfg(feature = "std")]
-impl std::error::Error for TryFromExitStatusError {}
+impl Error for TryFromExitStatusError {}
 
 #[cfg(test)]
 mod tests {
@@ -95,11 +94,8 @@ mod tests {
         );
     }
 
-    #[cfg(feature = "std")]
     #[test]
     fn source_exit_code_range_error() {
-        use std::error::Error;
-
         assert!(ExitCodeRangeError.source().is_none());
     }
 
@@ -188,8 +184,6 @@ mod tests {
     #[cfg(feature = "std")]
     #[test]
     fn source_try_from_exit_status_error() {
-        use std::error::Error;
-
         assert!(TryFromExitStatusError::new(Some(1)).source().is_none());
         assert!(TryFromExitStatusError::new(None).source().is_none());
     }
diff --git a/src/exit_code.rs b/src/exit_code.rs
index e380b67..b744ae9 100644
--- a/src/exit_code.rs
+++ b/src/exit_code.rs
@@ -10,7 +10,7 @@
 mod convert;
 pub mod result;
 
-use core::fmt;
+use core::{error::Error, fmt};
 
 /// `ExitCode` is a type that represents the system exit code constants as
 /// defined by [`<sysexits.h>`].
@@ -287,8 +287,7 @@ impl fmt::Display for ExitCode {
     }
 }
 
-#[cfg(feature = "std")]
-impl std::error::Error for ExitCode {}
+impl Error for ExitCode {}
 
 #[cfg(feature = "std")]
 impl std::process::Termination for ExitCode {
@@ -663,11 +662,8 @@ mod tests {
         assert!(ExitCode::Config.is_failure());
     }
 
-    #[cfg(feature = "std")]
     #[test]
     fn source_exit_code() {
-        use std::error::Error;
-
         assert!(ExitCode::Ok.source().is_none());
         assert!(ExitCode::Usage.source().is_none());
         assert!(ExitCode::DataErr.source().is_none());